1. Field of the Invention
The present invention relates to a device for operating a pair of members to be operated, such as brake shoes in a drum brake, so as to mechanically move these members away from each other through the manipulation of a lever, and in more detail, a device for detachably connecting a control cable to the lever.
2. Description of the Related Art
As to a control cable connecting device for the above-mentioned operating device, there has conventionally been known, for example, a device as shown in FIGS. 10a and 10b for detachably connecting a brake cable with a lever for operating a drum brake, which is disclosed in U.S. Pat. No. 5,311,793.
Referring to FIGS. 10a and 10b, there are shown a pair of brake shoes 1, 2 as members to be operated, a bracket 3, a lever 4, and a brake cable 5 as a control cable, which interact with one another as explained as follows, so as to constitute an operating device 6 for a drum brake.
The bracket 3 is formed at its one end with a cut-out 3a to which one of the brake shoes 1 is engaged, and the bracket 3 is provided at the other end with the lever 4 pivotally journalled at its proximal end by means of a pivot pin 7, while the lever 4 is formed at the proximal end with cut-outs 4a to which the other brake shoe 2 is engaged.
The lever 4 is further formed at its free end with cut-outs 4b to which an end fitting 5a of the brake cable 5 is engaged in a cable pulling direction.
With this arrangement, when a cable pulling force is inputted to the lever 4 through the brake cable 5, in the direction indicated by the arrow W, the lever 4 is rotated around the pivot pin 7 in the corresponding direction to push the brake shoe 2 outward.
Meanwhile, the rotation of the lever 4 around the pivot pin 7 applies a reaction force to the bracket 3 through the intermediary of the pivot pin 7, and accordingly, the bracket 3 is also pushed outward together with the brake shoe 1.
As a result, the brake shoes 1, 2 are moved away from each other and are pressed against the inner peripheral surface of a brake drum which is not shown, whereby a braking operation can be carried out.
The operating device 6 for a drum brake is preferably constituted in such manner that the brake cable 5 can be engaged with or disengaged from the cut-outs 4b of the lever 4 while the drum brake is incorporated in useable condition, and accordingly, the operating device 6 is further incorporated therein additionally with the following arrangement.
That is, as clearly shown in FIG. 10a, the bracket 3 is forked, except the end part where the cut-out 3a is formed, so as to have a space which is defined by a pair of opposed legs 3b, 3c and an inner end wall 3d, in which space the lever 4 is accommodated.
Further, the lever 4 is also forked, except the proximal end in which the pivot pin 7 and the cut-outs 4a are provided, so as to define a space between a pair of opposed legs 4c, 4d, though which space the brake cable 5 can pass.
Moreover, the distance between the pair of opposed legs 4c, 4d is selected such that the end fitting 5a of the brake cable 5 cannot pass through the space and the opposed legs 4c, 4d are formed respectively with the abovementioned cut-outs 4b for engaging the end fitting 5a. 
As clearly shown in FIG. 10b, the distance xe2x80x9cAxe2x80x9d as a gap between the free end face of the lever 4 and the inner end wall 3d of the bracket 3 is set to be such a size that the end fitting 5a can pass through, and a V-shaped leaf spring 8 is interposed so as to block the above gap, one leg 8a of the leaf spring 8 is made into close contact with the inner end wall 3d. 
The other leg 8b of the leaf spring 8 is made into close contact with the free end face of the lever 4 to define a convergent tapering space 9 between the other leg 8b and the free end face of the lever 4, which convergent tapering space 9 guides the end fitting 5a upon insertion of the latter which will be explained hereinafter.
As to the engagement of the brake cable 5, the end fitting 5a indicated by the two-dot chain line in FIG. 10b is inserted into the space 9 from the outside of the drum brake, and then, the brake cable 5 and its end fitting 5a are pushed as indicated by the arrow xcex1.
At this time, the end fitting 5a further advances while elastically deforming the spring leg 8b in a direction indicated by the arrow xcex2 with using the free end face of the lever 4 as a reaction force receiver. When the end fitting 5a overrides the free end face of the lever 4, the end fitting 5a is pushed by elastic restoration of the spring leg 8b in a reverse direction against which indicated by the arrow xcex2 so that the end fitting 5a is engaged with the cut-outs 4b. 
It should be noted that this elastic restoration of the spring leg 8b makes it possible to prevent the end fitting 5a from disengaging from the free end of the lever 4.
Upon detaching the brake cable 5, the spring leg 8b is elastically deformed in the direction indicated by the arrow xcex2 with use of a suitable tool inserted from the outside of the drum brake, and in this condition, in reverse order of the aforementioned steps, the end fitting 5a is disengaged from the cut-outs 4b, and then the brake cable 5 is pulled out so as to be removed.
In the above-mentioned conventional device for connecting the control cable for the drum brake, since the end fitting 5a of the brake cable 5 is allowed to pass through the gap between the free end face of the lever 4 and the inner end wall 3d of the bracket 3 so as to carry out engagement or disengagement of the brake cable 5 relative to the free end of the lever 4, and further, since it is necessary to normally block this gap with the V-shaped leaf spring 8 in order to prevent the end fitting 5a from disengaging from the free end of the lever 4, the gap required for passing the end fitting 5a as indicated by xe2x80x9cAxe2x80x9d in FIG. 10b should be set to a value which is larger than the sum of the diameter of the end fitting 5a and the value twice as large as the thickness of the V-shaped leaf spring 8.
Accordingly, there has been a problem such that the overall length of the operating device 6 becomes longer, and further, in such a case that the overall length of the operating device cannot be increased due to design restriction, since the distance xe2x80x9caxe2x80x9d from the center of the pivot pin 7 to the end fitting 5a of the brake cable 5 cannot be increased, that is, the lever ratio (a/b) of the lever 4 which is the ratio between the distance xe2x80x9caxe2x80x9d and the distance xe2x80x9cbxe2x80x9d from the center of the pivot pin 7 to the cutouts 4b cannot be increased, there is caused such a problem that the brake operating force becomes larger.
Thus, it has not been able to satisfy both requirements of reducing the brake operating force and of shortening the overall length of the operating device 6.
An object of a first aspect of the present invention is to provide a device for connecting a control cable, in which an end fitting of the control cable can be inserted into a position between the a journalled portion and the free end of the lever so as to be engaged with or disengaged from the free end of the lever, whereby eliminating above-mentioned problems inherent to conventional operating devices, that is, the problems such that the overall length of the operating device become longer and the brake operating force becomes larger due to the lever ratio of the lever to be ensured, and whereby satisfying both requirements of shortening the overall length of the operating device and of reducing the brake operating force.
To the end, there is provided a device for connecting a control cable for use in an operating device comprising
a strut of which one end is engaged with one of members to be operated,
a lever which is pivotally journalled to the other end of the strut and is engaged with the other of said members, and
a control cable having at its one end an end fitting which is adapted to be engaged with a free end of the lever in a cable pulling direction,
when applying cable pulling force to a free end of the lever by means of the control cable, the lever and strut being urged to be rotated relative to each other around the journalled portion so as to urge said members to be operated, away from each other, characterized in that:
said end fitting of the control cable can be inserted into a position where being between the journalled portion and the free end of the lever in a reverse direction against the cable pulling, and thereafter said end fitting of the control cable can be engaged with the free end of the lever.
Accordingly, it is possible to eliminate the necessity of setting an insertion gap between the free end face of the lever and the strut, and accordingly, the overall length of the operating device can be shortened by a degree corresponding to a decrease of the insertion gap, while the lever ratio of the lever can be increased to reduce the operating force, thereby satisfying both requirements of shortening of the overall length of the operating device and of reducing the operating force of the operating device.
An object of a second aspect of the present invention, is to provide a device for connecting a control cable, which is arranged to inexpensively achieve the functional effects and advantages exhibited by the first aspect of the present invention.
To the end, in addition to the first aspect of the present invention, there is provided a device for connecting a control cable, characterized in that the lever is composed of a pair of planar members opposed to each other, which planar members are coupled with each other at a portion corresponding to the proximal end of the lever to be pivotally journalled to the other end of the strut, and which planar members are spaced from each other at a portion corresponding to the free end of the lever so as to define a narrow gap between the planar members, having a size which allow a cable itself of the control cable to pass therethrough but which inhibits the end fitting of the control cable from passing therethrough, and to define a wide gap between the planar members at a longitudinally middle portion so as to step down to the narrow gap, having a size which allow the end fitting of the control cable to pass therethrough.
When engaging the end fitting with the free end of the lever, it can be accomplished by steps of firstly inserting the end fitting into the lever through the wide gap, and of shifting the end fitting toward the free end of the lever. Accordingly, the functional effects and advantages of the first aspect of the present invention can be achieved inexpensively by use of structure which can be formed by press work.
An object of a third aspect of the present invention is to provide a device for connecting a control cable, which can enhance the workability upon insertion of the end fitting of the control cable during attaching operation of the control cable.
To the end, in addition to the second aspect of the present invention, there is provided a device for connecting a control cable, characterized in that the end fitting of the control cable has a shape in which one side is longer than the other side as viewed in the longitudinal direction of the control cable, and the wide gap has a size with which the length of the one side of the end fitting can pass through the wide gap.
When engaging the end fitting with the free end of the lever, it can be accomplished only by inserting the end fitting so that the long side thereof is directed orthogonal to the planar members of the lever, and with the posture thereof being held as it is, by shifting the end fitting toward the narrow gap between the planer members without rotating the end fitting.
Accordingly, it is possible to enhance the workability of connecting operation of the control cable to the operating device.
An object of a fourth aspect of the present invention is to provide a device for connecting a control cable, which can reduce the widthwise dimension of the operating device.
To the end, in addition to the second aspect of the present invention, there is provided a device for connecting a control cable, characterized in that the end fitting of the control cable has a shape in which one side is longer than the other side as viewed in the longitudinal direction of the control cable, and the wide gap has a size with which the length of the other side of the end fitting can pass therethrough, but the length of the one side cannot pass therethrough.
Although the end fitting should be turned by an angle of 90 deg. around the axis of the cable after the end fitting is inserted through the wide gap, the overall width of the operating device can be reduced by a degree corresponding to a decrease in width of the wide gap.
An object of a fifth aspect of the present invention is to provide a device for connecting a control cable, in which the end fitting of the control cable can be inserted even though the lever is not held, and accordingly, the control cable can be attached after the operating device is attached in useable condition, thereby it is possible to facilitate the handling and the conveyance of the assembly to which the operating device is attached.
To the end, in addition to any one of the first to the fourth aspect of the present invention, there is provided a device for connecting a control cable, characterized in that the lever is provided with an end fitting stopper for receiving the end fitting of the control cable upon insertion thereof so as to determine an insertion position thereof, and the strut is provided with a lever abutting part for restricting the rotation of the lever relative to the strut in the direction of insertion of the end fitting.
The end fitting does not interfere with any other component when the end fitting has been inserted into the wide gap, and a worker can sense such a fact that the insertion work of the end fitting has been completed, thereby it is possible to facilitate the engagement or disengagement of the end fitting of the control cable.
Further, the end fitting can be inserted into the lever even though the lever is not held, and accordingly, the control cable can be connected to the operating device which has been attached in useable condition. Thereby it is possible to facilitate the handling and the conveyance of a unit such as a drum brake or the like in which the operating device is incorporated.
An object of a sixth aspect of the present invention is to provide a device for connecting a control cable, which allows a worker to sense the completion of insertion work of the end fitting.
To the end, in addition to any one of the first to fourth aspects of the present invention, there is provided a device for connecting a control cable, characterized in that the strut is provided with an end fitting stopper for receiving the end fitting of the control cable upon insertion thereof so as to determine an insertion position thereof.
The end fitting does not interfere with any other component upon insertion thereof into the wide gap, and a worker can senses completion of the insertion work of the end fitting, thereby it is possible to facilitate the engagement or disengagement of the end fitting of the control cable.
An object of a seventh aspect of the present invention is to provide a device for connecting a control cable which can exhibit functional effects and advantages similar to those exhibited by the fifth aspect of the present invention with use of another means which is different from the fifth aspect of the present invention.
To the end, in addition to any one of the first to fourth, there is provided a device for connecting a control cable, characterized in that there is provided on the strut the lever abutting part for restricting the rotation of the lever relative to the strut in the direction of insertion of the end fitting of the control cable.
The end fitting can be inserted even though the lever is not held, and accordingly, the control cable can be connected to the operating device which has been attached in useable condition. It is possible to achieve, with use of another means different from the fifth aspect of the present invention, the functional effects similar to those attained, thereby such that the handling and the conveyance of a unit such as a drum brake which is attached with the operating device can be facilitated.
An object of an eighth aspect of the present invention is to provide a device for connecting a control cable which can simply and inexpensively achieve the functional effects of the sixth and the seventh aspects of the present invention by structure which can be formed with use of press work.
To the end, in addition to the sixth or seventh aspect of the present invention, there is provided a device for connecting a control cable, characterized in that the strut is composed of opposed side walls between which the lever is interposed on opposite sides in the direction of the rotational axis of the lever, and a bridge part connecting between the opposed side walls which bridge part serves as the end fitting stopper, the lever abutting parts or both of them.
The functional effects of the sixth or seventh aspect of the present invention can be simply and inexpensively achieved by a structure which can. be formed with use of press work.
An object of a ninth aspect of the present invention is to provide a device for connecting a control cable, which can simply and inexpensively achieve functional effects obtained by both seventh and eighth aspects of the present invention by structure which can be formed with use of press work.
To the end, in addition to the eighth aspect of the present invention, there is provided a device for connecting a control cable, characterized in that the strut is provided with two bridge parts one of which is arranged in opposition to an intermediate part between the journalled portion and the free end of the lever so as to serve as the end fitting stopper, and the other one of which is located in the vicinity of the journalled portion of the lever so as to serve as the lever abutting part.
The functional effects and advantages exhibited by both seventh and eighth aspects of the present invention can be simply and inexpensively achieved by a structure which can be formed with use of press work.
An object of a tenth aspect of the present invention is to provide a device for connecting a control cable, which can prevent the end fitting of the control cable from interfering with another component when the end fitting is engaged with the free end of the lever after insertion.
To the end in addition to the eighth or ninth aspect of the present invention, there is provided a device for connecting a control cable, characterized in that the bridge part serving as the end fitting stopper is provided with an end fitting guide piece extended toward the narrow gap.
The end fitting of the control cable does not interfere with any other component when the end fitting is engaged with the free end of the lever after insertion, thereby it is possible to enhance the workability for connecting the control cable.
An object of an eleventh aspect of the present invention is to provide a device for connecting a control cable, which can prevent the end fitting of the control cable from interfering with any other component even if the control cable is slackened after the end fitting has been engaged with the free end of the lever.
To the end, in addition to the tenth aspect of the present invention, there is provided a device for connecting a control cable, characterized in that the end fitting guide piece is extended to a position above the narrow gap.
The end fitting can be prevented from interfering with another component even if the control cable is slackened after the end fitting has been engaged with free end of the lever.
An object of a twelfth aspect of the present invention is to provide a device for connecting a control cable, in which the slide motion between the end fitting and the lever becomes smooth in a condition such that the end fitting is engaged with the free end of the lever, so that the durability of the operating device can be enhanced.
To the end, in addition to any one of the first to eleventh aspects of the present invention, there is provided a device for connecting a control cable, characterized in that the engagement of the end fitting of the control cable with the free end of the lever is obtained through cylindrical surfaces.
The slide motion between the lever and the end fitting becomes smooth in a condition such that the end fitting is engaged with the free end of the lever, as a result of this it is possible to enhance the durability of the operating device.